News Coverage
Fire retardants pose graver risk than thought
Health-threatening polybrominated diphenyl ethers accumulate in body fat
Published April 1, 2004
New findings confirm scientists' fears that a class of fire retardant chemicals injected into everything from television sets to sofa cushions to drapes and carpeting have become this generation's version of PCBs -- a ubiquitous environmental toxin that accumulates in body fat and sticks around for years, if not decades.
The research shows the chemicals -- polybrominated diphenyl ethers, or PBDEs -- are growing exponentially in the environment, showing up in tissue samples of harbor seals, San Francisco Bay fish and, more alarmingly, in breast milk of nursing mothers.
In some cases, the levels exceed those of PCBs -- an insulating fluid and coolant used in transformers and banned in the United States since 1979 -- at the peak of their use.
Most worrisome, however, are different studies showing PBDE contamination in fish, seals and some nursing mothers approach and even exceed levels found to cause harm in laboratory animals, said Tom McDonald, a scientist with the reproductive and cancer hazard assessment center of the state Office of Health Hazard Assessment.
The studies also found that sunlight breaks down some PBDEs thought to be harmless, transforming them into toxic compounds.
In laboratory tests, certain PBDEs have impaired brain development and been linked to hearing loss, delayed puberty, decreased sperm counts and alterations to ovary cell structure. It doesn't take much, either, McDonald said. Those studies show harm at concentrations ranging from 300 to 1,000 parts per billion.
One part per billion is roughly equivalent to a drop of water in a backyard swimming pool. Half of Americans today, according to various studies, are believed to have PBDE contamination in the 70 parts-per-billion range or greater.
California and the European Union have banned what are considered the most hazardous PBDEs, a family of 209 chemicals that does a remarkable job retarding fire in hard-to-treat products, such as foam cushions and plastic computer and television casings. California's ban doesn't apply until 2008, though manufacturers say they intend to start phasing out the chemical next year.
The good news is that once PBDE use stops, environmental contamination tends to fall off. German sewage sludge, for instance, where PBDE use has fallen to just a fraction of that in the U.S., contains one-tenth to one-hundredth the PBDEs found in the city of Palo Alto's sewage, according to a city study.
Still, levels in the U.S. are growing. "For many individuals, PBDEs have surpassed PCBs (in the body)," McDonald said. The environment, particularly in California where fireproofing rules rank among the strictest in the country, has seen exponential growth in PBDEs in the past 10 years -- a rate that doesn't appear to be slowing, according to McDonald and other state scientists.
An Environmental Working Group test of breast milk from 20 first-time mothers found the substance in every sample, with the average level 75 times that of similar European studies.
Several efforts are afoot to curb that. Wednesday activists and staff members of Assemblywoman Wilma Chan, D-Oakland and sponsor of the California law banning two types of PBDEs, announced a multi-lingual effort warning anglers of the dangers of eating too many San Francisco Bay fish. The effort also includes outreach to public health clinics and other places to alert pregnant women, who are particularly vulnerable.
And in Congress, Reps. Hilda Solis, D-El Monte, Lynn Woosley, D-Petaluma, and Diana DeGette, D-Colorado, on Wednesday introduced a bill taking California's ban one step further. It seeks a nationwide moratorium on the two chemicals banned in California, plus any precursor fire retardant shown to break down into one of the banned compounds